Traffic signaling system



May 27, 1941. L. A. CLARK 2,243,088

I TRAFFIC SIGNALING SYSTEM Filed April 7, 1939 l 2 Sheets-Sheet 1 Zen :4 (Van I Qua/M4 May 27, 1 941. L CLA K 2,243,088

TRAFFIC SIGNALING SYSTEM Filed April 7, 1939 2 Sheets-Sheet 2 VIII/4 111114 Ema/who's Paten'ted May 27, 1941 UNITED STATES PATENT OFFICE TRAFFIC SIGNALING SYSTEM Leroy A. Clark, Miami, Fla., assignor to Mercury Timer Company, a corporation of Florida Application April 7, 1939, Serial No. 266,637

2 Claims. (Cl. 177-337) This invention relates to traflic signaling systems, and more particularly to a very simple and economical circuit making and breaking mechanism for controlling traffic lights and to a new arrangement of wiring by virtue of which the likelihood of getting the various lights wholly out of synchronism, or the likelihood of the short-circuiting of any of the lights under attempts of inexperienced persons to adjust the timing of the same, will be prevented.

One embodiment of the invention by virtue of which I accomplish the foregoing objects is illustrated in the accompanying drawings, wherein:

Figure 1 is a plan view of the timing mechanism of the invention;

Fig. 2 is a front elevation of said timing mechanism;

Fig. 3 is an end elevation of the timing mechanism;

Fig. 4 is a fragmentary view of one of the toothed disks hereinafter described;

Fig. 5 is an enlarged fragmentary sectional view through one of the rock shafts which carry the mercury switches;

Fig. 6 is a vertical sectional view upon line 66 of Fi 5;

Fig. '7 is a diagrammatic view of the wiring;

Fig. 8 is a fragmentary sectional view of the two central disks of the timing mechanism, and

Fig. 9 is a fragmentary sectional view of the right-hand disk of the timing mechanism.

Like numerals designate corresponding parts throughout the several figures of the drawings.

The timing mechanism is supported upon any suitable base 5, carrying an upstanding wall Ii, of Bakelite or other suitable insulating material. A synchronous motor I, such as is commonly em- I ployed in the driving of electric clocks, drives through any suitable gearing, indicated at 8, to a main drive shaft 9. The motor serves to drive this shaft 9 at a uniform and determined rate of speed, as for example, one revolution per I minute.

1 one direction or the other against balls I6 or I9, which have rolling mounting upon the ends of stub shafts 20, 2 I. These stub shafts in turn are carried at the lower ends of the arms 22 of the crank of wishbone formation. The upper portion 23 of this crank is bound by a nut 24 upon an angular portion 25 of a rock shaft 26 (see Fig. 5). Shaft 26 in turn is mounted for oscil lation in a sleeve 21.

This sleeve 21 is held in place in the wall 6 by nuts 28. A collar 29 is held in place upon shaft 26 by a nut 30. A block 3| has a 10st motion connection with shaft 26 through the medium of a pin 32, which engages in an arcuate slot 33 of the block, said pin being carried by a disk 34, which is splined upon or otherwise held against turning with respect to rock shaft 26.

As the disks I3 and I4 rotate, the cams act to rock the shaft 26 first in one direction and then in the other. move block 3| to thereby tip the tube 35 of a master mercury switch, said tube being carried by an arm 36 which projects from the face of the block 3|. The lost motion connection described permits the block to fall over quickly and to thereby secure a quick closing of the circuit when the block has been moved to past-center position by the action of the pin 32.

The structure illustrated in Fig. 5 is duplicated with respect to additional mercury switches 31 and 38, and the same reference characters have been applied. However, the rock shafts 26 26 of the mercury switches 31 and 38 do not carry wishbone crank arms but carry simple crank arms 33 and 40 which coact with cams M and 42 of the disks I2 and I5 respectively. Springs 43, 44 tend to move the crank arms 39 and 40 toward their coacting cams to bring anti-friction balls 45, 46 into engagement with said cams.

An important feature of the present invention, and one which I believe to be novel with me, resides in making the disks I2 and I3 to turn in unison with sleeve II and making the disks I4 and I5 to turn in unison with each other, and in further providing means whereby the unit comprising I I, I2 and I3 may be adjusted as a whole, circumferentially, with respect to the unit comprising the elements 9, I4 and I5, while in addition providing for means for adjusting the cams 4| and 42 over the faces of the disks I2 and I5, respectively.

The means by which this is accomplished is best illustrated in Figs. 8 and 9. Here it is shown that the disk I3 and its cam I6 carry a vertical pin 41. This pin may be moved upwardly through guides 48 against the tension of a spring 49 to lift a transverse pin 50, carried by pin 41, out of This causes the pin 32 toengagement with the teeth iii of disk i l. When this is done, the disks may be adjusted circumferentially with respect to each other to give any desired position of the cams i6 and i! in relation to each other.

When the pin 56 is released, it drops into one of the notches between the teeth, and in Fig. 4, I have illustrated that the toothed disks may have their notches numbered with numerals a from one to sixty, indicative of seconds. The positioning of the cams it and i1 determines the time of change between the north and south red light and the east and west red light; while the positioning of the cams ti and #42 upon the disks determines the period through which the amber light will show before the green light comes on.

The manner in which this is accomplished may easily be understood by referring to Fig. '1. In this figure, indicates a conductor constituting a source of incoming current. The mercury switches that I employ, while being of a conventional type, differ from simple circuit closers in that they complete one circuit when tipped in one direction and complete another circuit when tipped in the other direction.

For example, when 35 is tipped to the right, a circuit is completed at I) through the contact bar c of the mercury switch to conductor 53. This conductor is connected to the contact bar d of the mercury tube but at a point ahead of said mercury tube 38, a conductor 54 connects 53 with the north and south red light 55. When the tube 35 is tipped in the opposite direction, a circuit is completed at e between contact bar and a conductor 55 which leads to the contact bar f of mercury tube However, at a point ahead of mercury tube 3?, a conductor 5! leads from 56 to the east and west red light 58.

Thus it will be seen that the tube 35, which constitutes the master switch, controls the two red li hts under the influence of the setting of the two complete units l2, l3 and [4, I5, and that this control of the red lights which determines the duration of the complete cycle of operation of the switch is independent of the period of dwell between the amber and green lights of the north-south, east-west sides of the signal, this duration being determined by the time of tipping of 3'! and 33.

With tube 38 in the position illustrated in Fig. 7, a circuit is completed at 9 through conductor 59 to the east-west green light 69. With tube 38 tipped in the opposite direction, a circuit will be completed at it through a conductor El to the amber light 62 of the east-west side of the signal. In like manner, with the tube 31 tipped to the position illustrated in Fig. 7, a circult is completed at 2' through a conductor 53 to the amber t l of the north-south side of the signal. When tube 31 is tipped in the opposite direction, a circuit will be completed at 7' through a conductor 65 to the green light 66 of the north-south side of the signal.

The adjusting means for the cams 4|, 22 are very similar to those previously described with respect to Fig. 8. However, in this case (see Fig. 9), the guides 67 for the vertical pin d'i are not carried by a disk but are carried by a wall E8, constituting a part of the cam, and a tail 69 of the cam is traversed by shaft 9 and held in place by a collar '18 on said shaft. Upward movement of pin ti is against the tension of a spring H, and a transverse pin 12, carried by pin 41, engages in any of the notches between the teeth of the disks [2, l5.

Thus, in the case of the disks i2 and 15, the cams are swung around the faces of the disks to the desired position; while in the case of the structure of Fig. 8, the units Ii, 12, i3 upon the one hand, are adjusted as a whole with respect to the unit 9, l4, l5 upon the other hand, and the pin 50 (Fig, 8) looks these units in adjusted position with respect to each other.

In Fig. 3 I have illustrated a feature which may be employed or may be omitted, since the remainder of the structure will operate with or without it. In this figure, I have illustrated a disk I3, graduated as indicated at 14 after the manner of a clock dial and provided with sixty graduations. A pointer or hand is carried by a pin 16, which projects from the end of the shaft 9, and thus the movement of the hand is in unison with shaft 9.

This facilitates the work of the oflicer charged with synchronizing lights at different intersections, because with the second hand of his watch set in synchronism with the hand 15, he can, if the disk 74 and hand it be exposed to view, drive along the street and at a glance determine J'ust how much any given signal is out of synchronism with its fellows.

I am aware of the fact that it is quite old in the art to provide circuit closers embodying a plurality of contact making and breaking members, and even to use tipping mercury switches in conjunction therewith. However, I do not know of any mechanism embodying such extreme simplicity as that disclosed in this application or embodying the master switch controlling the relation of the north and south cycle with respect to the east and West cycle, while leaving such master switch wholly free of accidental short-circuiting or disagreement due to the effort of any person to adjust the auxiliary switches controlling the amber and green lights of the north and south side of the signal, upon the one hand, and the east and west side of the signal upon the other. It will be very clear that nothing that an inexperienced person might do in endeavoring to adjust the relationship of the amber and green lights could bring about any disorganization of the. main cycle of operation.

In those trafiic signals having a plurality of switches all of equal value, one of which controls one red light, another of which controls the other red light, another of which controls one green light, another of which controls the other green light, another of which controls one amber, and another of which controls the other amber light, all of said switches being independently adjustable, it is very easy to get the various lights so mixed up that it is almost impossible to straighten them out. In an endeavor to do so, the inexperienced person frequently connects two positives to the same light, resulting in short-circuiting the lights, burning them out, and bringing about confusion in traffic. Nothing of this sort can happen with the signal of the present invention.

While the mechanism that I have devised for accomplishing the foregoing results, and which I have illustrated herein, has been found to be highly eificient in actual tests and is very economical of construction and certain in operation, I wish it to be understood that the invention is not limited to this particular mechanism.

It is clear that the skilled engineer may find other Ways of utilizing the principles of the invention through mechanism of another type. Therefore, it is to be understood that the invention includes within its purview whatever changes fairly come within either the terms or the spirit of the appended claims.

Having described my claim is:

1. In a system of the character described, a group of east-West lights comprising a stop, a go and a caution light, a group of northsouth lights comprising a stop, a go and a caution light, a master switch which when in one position closes a circuit energizing one stop light, and when in another position closes a circuit energizing the other stop light, said two circuits being independent of and including none of the go or caution lights, a pair of circuits for the east-west group in which the caution and go lights of said group are respecinvention,

tively included, a pair of circuits for the north- 0 south group in which the caution and go lights of said group are respectively included, an auxiliary, two-position switch for each of said pairs of circuits, said switches in one position energizing its associated caution light, and in its other position energizing its associated go light, and means for supplying energizing current for said pairs of circuits to the auxiliary switches through and under control of the master switch.

what I 2. In a system of the character described, a group of east-west lights comprising stop, caution, and go lights, a group of north-south lights comprising stop, caution, and go lights, a master switch, a pair of auxiliary switches, circuits including said switches and lights, a pair of uniformly moving units, means for adjusting said units bodily with respect to each other, a member carried by each of said units, one of which shifts the master switch to circuit completing position in one direction and the other of which shifts the master switch to circuit completing position in the other direction, the position of said members with respect to each other determining the time of shifting of the master switch,

and a member carried by each of said units and adjustable as to position upon said unit and engaging and shifting the auxiliary switches respectively, to and from circuit-closing position, the said circuits including circuits controlled by the master switch and including no caution or go light which when energized illuminate the stop lights of the respective signals independently of the auxiliary switches, and additional circuits controlled by and including both the master switch and the auxiliary switches, which when energized illuminate either the go or caution lights of the signals according to the position to which the auxiliary switches have been shifted.

LEROY A. CLARK. 

